Microstructure Simulation Of Unidirectional Solidification Based On Dendrite Envelope Tracking Method

Directional solidification and single crystal will be the development direction of the casting microstructure simulation, the unidirectional solidification columnar crystal casting compared with general one can reduce segregation and rarefaction et al, the grain parallel to principal axis of stress can basically eliminate transverse grain boundary normal to principal axis of stress. It improves the elevated temperature strength, creep deformation, persistent characteristic, thermal fatigue performance and makes the mechanical property have a new forward leap. Furthermore, for face-centered cubic magnetic material (such as iron et al), when columnar crystal orientation at-cast is <001>, the magnetism can be improved greatly.The research and development of casting solidification process are reviewed, the model of the Finite Difference Method (FDM) temperature field is introduced and present research and problem of solidification process modeling are put forward in this paper. The boundary condition and latent heat is taken into account by FDM. The model suitable to the practical situation is adopted. Based upon Temperature field, concentration field of casting directional solidification is simulated. The microscopic model takes into account nucleation of new grains in the undercooled melt, the kinetics of the dendrite tips. According to the character of directional solidification, liquid/solid interface and the grain growth are dealt with dendrite envelope tracking technique. The software is programmed for the growth and microstructure of columnar crystals in unidirectional solidification by Fortran and VC++.By the columnar crystal micro-simulation, we can control microstructure and link microstructure with mechanical property together to improve the mechanical property of product and afford credibility technique for the exploitation of new material and new process of foundry.